I am finishing up an intake manifold gasket (upper & lower) change 2003 Grand Prix w/ a 3.8 w/o a super charger. While I was in there I cleaned the throttle body and Mass Air Flow Sensor. On first start up it was idling at 2500 RPM then spiked up to 4000 RPM. If I disconnect the Idle Air Control it still idles at 2500 RPM but does not spike up. Disconnecting the Throttle Position Sensor or Mas Air Flow Sensor has not effect on the idle. Disconnecting the air flow sensor in the intake tube causes to idle to raise slightly. The check engine light comes on immediately. I don't have a code scanner on hand to check the code. I also checked to make sure the throttle cable was letting the throttle body close all the way and it is, has just a slight amount of slack in both cables. Where should I look next? I am stumped.